DETERMINATION OF SOMATIC MUTANT FREQUENCIES AT GLYCOPHORIN-A AND T-CELL RECEPTOR LOCI FOR BIODOSIMETRY OF PROLONGED IRRADIATION

Purpose: To determine the variant frequencies (VF) at glycophorin A (G PA) and T-cell receptor (TCR) loci in persons exposed to prolonged ion izing radiation at different doses and to assess the significance of t he GPA and TCR assays for biodosimetry of prolonged irradiation. Mater ials and methods: The VF values were determined by means of flow cytom etry in 120 persons exposed between 1968-1996. Most exposures were in Chernobyl clean-up workers in 1986-1987. Results: A significant correl ation was shown between the N empty set GPA variant cell frequency and dose (r = 0.61, p < 0.0001). The slope of the linear regression was 6 .3 x 10(-6) N empty set mutant cells/Gy. Dose-dependent increase in th e TCR VF was found in the group with recent exposures (slope 2.1 x 10( -4) variant cells/Gy, r = 0.75, p = 0.0002). In the Chernobyl clean up workers who received doses less than 0.25 Gy the TCR VF unlike the GP A VF was significantly higher than in the control non-irradiated indiv iduals (p < 0.01 and p > 0.05 respectively). Conclusions: The GPA assa y has limited potential to be used as a biodosimeter of prolonged irra diation, at least in dose interval up to 2 0 Gy. The TCR assay is like ly to have greater potential in estimation of recent radiation exposur e than the GPA assay.